Master cylinders are in wide use in various industries, but particularly in the motor vehicle industry where they serve in conjunction with an associated slave cylinder to control various systems of the motor vehicle. For example, the brakes of a motor vehicle are typically actuated by slave cylinders located at the wheels of the vehicle and supplied with pressure fluid from a master cylinder actuated by the brake pedal of the vehicle. As a further example, the clutch of a manual transmission vehicles is often engaged and disengaged by a slave cylinder located at the clutch assembly and receiving pressure fluid from a master cylinder actuated by the clutch pedal of the vehicle. In both of the above examples, the master cylinder is directly and manually actuated by the vehicle operator by suitable actuation of the associated control pedal of the vehicle. Whereas manual actuation of a master cylinder is effective to produce the desired resultant action at the associated slave cylinder, there are situations where it would be desirable to provide power operation of the master cylinder as suitably instigated by the vehicle operator. For example, such a power operated master cylinder would be useful in a manual transmission vehicle to engage and disengage the vehicle clutch in response to a suitable signal from the vehicle operator.